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Isolation and partial characterization of murine O 6 ‐alkyiguanine‐DNA‐alkyltransferase: Comparative sequence and structural properties
Author(s) -
SantibanezKoref Mauro,
Elder Rhoderick H.,
Fan ChunYang,
Cawkwell Lynn,
McKie James H.,
Douglas Kenneth T.,
Margison Geoffrey P.,
Rafferty Joseph A.
Publication year - 1992
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.2940050212
Subject(s) - biology , microbiology and biotechnology , polyclonal antibodies , complementary dna , oligonucleotide , peptide sequence , biochemistry , leucine zipper , dna , amino acid , nucleic acid sequence , protein primary structure , gene , antibody , genetics
A cDNA encoding murine O 6 ‐alkylguanine‐DNA‐alkyltransferase (ATase) has been sequenced after isolation from total liver RNA by the polymerase chain reaction using oligonucleotide primers derived from the rat ATase cDNA sequence. Functionally active murine ATase protein has been expressed in Escherichia coli at high levels (about 2% of total protein) and purified to apparent homogeneity (molecular mass 26 kDa). In liquid hybridization experiments, anti‐human ATase polyclonal antibodies inhibited human but not rat or mouse ATase, whereas anti‐rat polyclonal antibodies inhibited rat and mouse but not human ATase. Both antibodies detected all mammalian ATases tested by western analysis so far. These results indicate some common epitopes and at least one unique human epitope. We compared the amino‐acid sequence of the murine ATase with those of other mammalian and bacterial ATases. The proteins of this family all have a large domain (approximately 70 amino acids) of highly conserved residues flanking the sequence PCHRV, which contains the alkyl‐accepting cysteine residue of the active site. No evidence was found in the sequences for helix‐turn‐helix, leucine‐zipper, or zinc‐finger motifs for DNA recognition and binding. Nuclear localization signals (basic‐residue‐rich regions) could not be uniquely identified in the mammalian members of the family. Outside of the conserved PCHRV region, there were major differences between prokaryotic and eukaryotic proteins at the primary structure level: there was a series of proline‐rich motifs, but these also varied between sequences. © 1992 wiley‐Liss, Inc.